<!DOCTYPE html>
<html>

	<head>
		<meta charset="UTF-8">
		<title></title>

		<head>
			<style type="text/css">
				table {
					border-collapse: collapse;
				}
				
				table,
				th,
				td {
					text-align: center;
					border: 1px solid black;
					font-size: 13px;
				}
				
				td {
					width: 140px;
					height: 28px;
				}
			</style>
			<script type="text/javascript">
				function show() {
					var et = document.getElementById("employees")
					console.info("et：")
					console.info(et);
					//et.lastChild表示tbody元素，et.lastChild.lastChild表示最后一行
					//et.lastChild.lastChild.firstChild表示最后一行的第一个单元格
					//et.lastChild.lastChild.firstChild.firstChild表示该单元格的文本节点
					var s = et.lastChild.previousSibling.lastChild.previousSibling.lastChild.previousSibling.innerHTML;//.firstChild;//.firstChild.nodeValue
					console.info("et.lastChild.previousSibling：")
					console.info(s);
					//var s = et.lastChild.lastChild.firstChild.innerHTML
					document.getElementById("showValue").value = s
				}
			</script>
		</head>

		<body>
			<table id="employees">
				<thead>
					<tr>
						<td>编号</td>
						<td>姓名</td>
						<td>电话号码</td>
						<td>月薪</td>
					</tr>
				</thead>
				<tbody>
					<tr>
						<td>100</td>
						<td>斯蒂芬</td>
						<td>1582198739</td>
						<td>2000</td>
					</tr>
					<tr>
						<td>101</td>
						<td>解决了</td>
						<td>1592198739</td>
						<td>2200</td>
					</tr>
				</tbody>
			</table>
			<p><input type="button" name="btn" value="表.lastChild.lastChild.firstChild.firstChild.nodeValue" onclick="show()" /></p>
			<p>获取到的值为：<input type="text" id="showValue" size="65" /></p>
		</body>

</html>